Have you taken the lense off? See if you can, then look to see if your mirror is damaged or misaligned. Go into your menu and do a mirror lock up, then back down. If it looks good put the lense back on and try taking a picture. You don't want to possible screw up your lense with a broken mirror. Sorry for your accident. Hope everything works out for you.

for example the infamous brick wall. Is it sharp left and right top and bottom -- of course needs to be a straight shot. Test both ends of the zoom range. Only worry if there are gross and obvious effects. If so, test another lens, question is the camera body bent too.

for example the infamous brick wall. Is it sharp left and right top and bottom -- of course needs to be a straight shot. Test both ends of the zoom range. Only worry if there are gross and obvious effects. If so, test another lens, question is the camera body bent too.

There are various posts on here that the D800 has a weakness when dropped such that the frame for the sensor can crack so the sensor itself is then out of alignment. It is not normally noticeable unless you pixel peep. As I said earlier my D800 seems to be fine

the thud might have fixed the infamous left side autofocus problem. If it has fixed it you need to describe to all the exact height of the fall, the surface impacted and all other relevant issues so that the rest of us can do the same to our D800's.